Monday, December 23, 2013

Prove the equality (1 + i*3^1/2 )^2 + (1 - i*3^1/2 )^2 = -4

We'll expand the squares from the left sides, using the
formula:


(a+b)^2 = a^2 + 2ab +
b^2


We'll put a = 1 and b =
i*sqrt3


(1 + i*sqrt3 )^2 = 1 + 2i*sqrt3 +
3i^2


But i^2 = -1


(1 + i*sqrt3
)^2 = 1 + 2i*sqrt3 - 3


We'll combine like
terms:


(1 + i*sqrt3 )^2 = 2i*sqrt3 - 2
(1)


Now, we'll expand the square (1 - i*sqrt3
)^2:


(1 - i*sqrt3 )^2 = 1 - 2i*sqrt3 -
3


(1 - i*sqrt3 )^2 = -2i*sqrt3 - 2
(2)


We'll add (1) and
(2):


2i*sqrt3 - 2 - 2i*sqrt3 - 2 =
-4


We'll eliminate like
terms:


-4 =
-4


The identity is
verified!

No comments:

Post a Comment

How is Anne's goal of wanting "to go on living even after my death" fulfilled in Anne Frank: The Diary of a Young Girl?I didn't get how it was...

I think you are right! I don't believe that many of the Jews who were herded into the concentration camps actually understood the eno...